Cask breather and gravity dispense?

[OvenHiker]

Hi,

I've been looking into the merits of cask breathers to prolong the shelf life of cask beer. I see that they are normally used in conjunction with a beer engine, but is it possible to use a breather to dispense directly from the cask by gravity? I like the idea of gravity dispensed beer at home, but I wouldn't be able to empty a cask within a few days of it being tapped.

If not, I guess the other option would be these 5 litre disposable steel casks which would be small enough to empty in reasonable time. My local microbrewery uses these and I've succesfully reused one but I doubt they'd last more than a few brews, so I'd prefer to use something like the new plastic pins at barleybottom with a breather if possible.

[flytact]

If you're going to be sealing up the cask after every session then forgo the breather and put a small amount of CO2 over the beer manually. Just make sure to vent it off before opening up the tap. In directly answering your question, I think a breather will do fine for you.

[OvenHiker]

... I think a breather will do fine for you.

Thanks fly, I was unsure whether the required drop in cask pressure to operate the breather needed to be made by something like a beer engine. So, opening the tap on a cask would also provide the required fall in pressure to open the breather valve to admit CO2 into the ullage?

I've never seen such an arrangement before, hence my query. I was worried that air was more likely to be drawn in through the tap when it is opened than CO2 through the breather valve. If anyone else has tried this arrangement I'd really like to know how it worked out?

[flytact]

Well, now you've got me thinking. The breathers only job is to replace the beer with CO2. Air should not be getting into the cask through the tap, it comes in through the vent. No vent, you get a vacuum and no beer. So, the breather is simply taking the place of the vent, CO2 in and not ambient. With a gravity system there should be no pressure drop.

[OvenHiker]

Perhaps I'm beginning to see the answer to my own question. Flytact: You might indeed get a vacuum without a vent, but you might also get the situation where air rushes in and liquid rushing out alternately, like the glug when you pour out a bottle. This would be bad as it would stir up the sediment and risk oxygenating the beer.

I guess the question is which is most likely to happen, the breather valve opening, air coming through the tap, both alternately, or nothing (vacuum). Has anyone tried it, maybe it's just not possible to use a breather and gravity dispense?

[Aleman]

There is no problem with using a cask aspirator and gravity dispensing from a cask . . . You need a special hollow spile to connect the cask breather to, but apart from that it all works fine . . . I've never seen air sucking back into a cask when they are used in this way.

[jim williams]

yeah, you're over thinking this. Al the breather is doing is displacing air with c02. I do what you're thinking at home with both a firkin and a pin. You won't have any problems at all. I've had cask beer on for 6 weeks in still drinkable condition.

[OvenHiker]

There is no problem with using a cask aspirator and gravity dispensing from a cask . . . You need a special hollow spile to connect the cask breather to, but apart from that it all works fine . . . I've never seen air sucking back into a cask when they are used in this way.

Fantastic! Thanks Aleman, that's put my mind at rest.

Ah, are you referring to the spiles like those shown with the breathers sold at Colin Farrar Brewery Services?

yeah, you're over thinking this. All the breather is doing is displacing air with c02. I do what you're thinking at home with both a firkin and a pin. You won't have any problems at all. I've had cask beer on for 6 weeks in still drinkable condition.

Thanks Jim, great to know that others are succesfully using this setup. Six weeks sounds perfect for what I want.

This forum is great!

[OvenHiker]

It's been a while, but I have finally got my cask breather setup sorted out. The cask breather comes from Paul at BarleyBottom and the cornelius post is connected to the lid using a post adaptor as a back nut and a S30 valve seal between the lid and the post.

The picture shows all the parts hooked up in my cellaring fridge which is kept at ~12C using a TC10 to control the fridge and tube heater. You can see the John Guest bulkhead that will be used to take the gas through the side of the fridge from the breather.

[OvenHiker]

However, I have found a problem with my setup. It appears that my concern that air might suck back into the cask was unfortunately well founded. It appears to be worse as the volume in the cask falls. It even appears to happen after changing the corny post for a no. 6 drilled rubber bung and breather spile, so I don't think it's the post and disconnect causing the problem.

I would really like to know whether my breather valve is duff or whether there simply isn't enough liquid to cause the pressure to drop enough for the valve to open. I am thinking of extending the tap with a short piece of tubing to see if that helps, but if anyone has any experience or advice, I'd really appreciate it.

[Aleman]

Sorry didn't realise that you meant plastic barrel when you said cask . . . Though you were talking about real casks.

What pressure do you have set on the regulator? I use around 20 psi on mine (the actual setting is pretty irrelevant as long as its highish). . . . If you suck on the pipe coming from the breather does the breather open? . . . Mine does with little effort, it could be stuck

[OvenHiker]

Sorry didn't realise that you meant plastic barrel when you said cask . . . Though you were talking about real casks.

Sorry Aleman - Yes, I did mean real casks in the original post. My two gallon barrels are a sort of stopgap to pins and/or firkins when I get around to finishing my 10 gallon setup, though I would expect it to work just as well with a small barrel.

What pressure do you have set on the regulator? I use around 20 psi on mine (the actual setting is pretty irrelevant as long as its highish). . . . If you suck on the pipe coming from the breather does the breather open? . . . Mine does with little effort, it could be stuck

I didn't receive an instruction manual with the breather, so I went with the advice in A Guide to Craft Brewing to set it to 15 psi (1 bar).
I had the same thought that the valve might be stuck, so yes, the breather does open with a little effort.

I'm not an expert on the physics of gases under pressure, but surely the behaviour would scale when using different sized casks/barrels? In which case, perhaps it is the design of the tap? The internal space of the taps on my pressure barrels are quite short compared proportionally to a typical cask tap. Any thoughts?

[Aleman]

I've never tried gravity dispense from plastic kegs or cornies, but suspect that the required vacuum just isn't being developed to open the cask breather. I have used a hand pump on a corny with no problem . . . which obviously develops the required vacuum

[OvenHiker]

Cheers Aleman, I wonder why the required vacuum is not being developed. Can't immediately see why it works for casks but not for plastic kegs?

Any physicists out there able to shine any light on this?

[OvenHiker]

A quick test with a five inch piece of PVC tubing on the end of the tap makes no difference.